On Thu 29-05-14 12:15:54, Johannes Weiner wrote: > The charging path currently starts out with OOM condition checks when > OOM is the rarest possible case. > > Rearrange this code to run OOM/task dying checks only after trying the > percpu charge and the res_counter charge and bail out before entering > reclaim. Attempting a charge does not hurt an (oom-)killed task as > much as every charge attempt having to check OOM conditions. Also, > only check __GFP_NOFAIL when the charge would actually fail. > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxx> > --- > mm/memcontrol.c | 33 +++++++++++++++++---------------- > 1 file changed, 17 insertions(+), 16 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index c3c10ab98355..46b3e37542ad 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2576,22 +2576,6 @@ static int mem_cgroup_try_charge(struct mem_cgroup *memcg, > > if (mem_cgroup_is_root(memcg)) > goto done; > - /* > - * Unlike in global OOM situations, memcg is not in a physical > - * memory shortage. Allow dying and OOM-killed tasks to > - * bypass the last charges so that they can exit quickly and > - * free their memory. > - */ > - if (unlikely(test_thread_flag(TIF_MEMDIE) || > - fatal_signal_pending(current) || > - current->flags & PF_EXITING)) > - goto bypass; > - > - if (unlikely(task_in_memcg_oom(current))) > - goto nomem; > - > - if (gfp_mask & __GFP_NOFAIL) > - oom = false; > retry: > if (consume_stock(memcg, nr_pages)) > goto done; > @@ -2613,6 +2597,20 @@ retry: > goto retry; > } > > + /* > + * Unlike in global OOM situations, memcg is not in a physical > + * memory shortage. Allow dying and OOM-killed tasks to > + * bypass the last charges so that they can exit quickly and > + * free their memory. > + */ > + if (unlikely(test_thread_flag(TIF_MEMDIE) || > + fatal_signal_pending(current) || > + current->flags & PF_EXITING)) > + goto bypass; > + > + if (unlikely(task_in_memcg_oom(current))) > + goto nomem; > + > if (!(gfp_mask & __GFP_WAIT)) > goto nomem; > > @@ -2641,6 +2639,9 @@ retry: > if (mem_cgroup_wait_acct_move(mem_over_limit)) > goto retry; > > + if (gfp_mask & __GFP_NOFAIL) > + goto bypass; > + > if (fatal_signal_pending(current)) > goto bypass; > > -- > 1.9.3 > -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>